An automotive catalytic converter is an emissions control device which may be incorporated into the exhaust system of a motor vehicle between the exhaust manifold and the muffler. The catalytic converter contains one or more catalysts, such as those based on platinum, palladium, or rhodium, which reduce the levels of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx) in the exhaust gas, thereby reducing the amount of these pollutants which would otherwise be emitted into the atmosphere from the vehicle. In a typical commercial catalytic converter, HC and CO in the exhaust are oxidized to form carbon dioxide (CO2) and water, and NOx is reduced to nitrogen, carbon dioxide, and water.
As a result of recent regulatory initiatives, motor vehicle emissions control devices, including catalytic converters, are now required to have longer useful lives. For example the US Environmental Protection Agency (EPA) in 1996 in 40 C.F.R. 86.094-2 increased the mileage for which automotive emission control elements must function from 50,000 to 100,000 vehicle miles. This requirement places severe demands on a catalytic converter, since a number of components introduced into the typical automotive internal combustion engine exhaust can act as a poison to the catalyst present in the converter.
In order to understand the effects of potential catalytic converter catalyst poisons, it is necessary to have a testing apparatus and procedure that will permit the evaluation of the long term effects of the individual variables which may affect the performance of the catalyst. Historically, an internal combustion engine has been used for such an evaluation, however, such an apparatus can be inconsistent, maintenance intensive, and expensive to operate. In addition, such an apparatus does not conveniently permit the separate evaluation of individual variables, such as the effects of constituents of the fuel and of constituents of the oil. Also, the engine oil consumption varies with engine age, operating temperature, speed and other variables, which are difficult to control.
A test apparatus and testing method are needed which overcome the foregoing deficiencies.